Spoiler alert! Sunday night on Discovery’s MythBusters, hosts Adam Savage and Jamie Hyneman took on the most requested myth in the show’s history: Did Jack (Leonardo DiCaprio) needlessly die in James Cameron’s Titanic, or could he and Rose (Kate Winslet) have both survived on that wooden board? Cameron himself appeared in the episode, explaining that the film’s rerelease in 3D reignited the debate and he needs to know whether the movie got it right, or, as he says fans put it to him in dozens of emails every day, “Rose is a selfish so-and-so and Jack’s an idiot.” The answer…

It is plausible that Rose and Jack could have both stayed afloat on the board and survived hypothermia just long enough to be rescued — but only if they’d thought to tie Rose’s life jacket underneath the board to help with its buoyancy. Otherwise, the weight of both their bodies would have sunk the board low enough in the freezing water that they both would have died. Let’s break it down further:

• For the hypothermia tests, Cameron said Fifth Officer Harold Lowe, who rescues Rose in the film, began his search about 20 minutes after the ship sank and continued for about 45 minutes, according to survivors. Since Rose is one of the last people to be rescued in the film — the officer hears her whistle right as he’s about to give up — they decided 63 minutes is fair. To test whether a human could have survived that long in freezing conditions, Jamie built ThermoMan, a dummy with gelatin flesh and a water-heated copper cardiovascular system that was rigged to monitor body temperature. Once they had him at 98.6° F, they submerged him in 29° water and timed how long it took him to reach deadly hypothermia. They pronounced Jack dead at 51 minutes because his body temperature dropped to below 85° F, which means he would have experienced loss of motor control and not been able to hold onto the board. So the movie had that right: Jack would have drowned.

In the second hypothermia test, ThermoMan was warmed back up to 98.6°, dressed in his wet clothes, and set hovering above the freezing water in 29° F air. Though the drop of body temperate drop was nearly identical, the difference was, when he reached the temperature that would cause him to become immobile, he was laying safely on top of the board. He wouldn’t have drowned. That bought him more time. As long as he was rescued before his body temperature dropped below 82° F, he could be revived. At 63 minutes, ThermoMan’s core body temp was 82.5° F. So technically, Rose would have been alive to be rescued.

What the show didn’t address though: How would she have been able to pry Jack’s frozen hands off the board so she could slide off and then swim to get a hold of the whistle that she blows to signal Lowe in the movie if she had no motor control?

• As for whether the board could have supported both Jack and Rose for 63 minutes, Adam first did a small-scale test using dolls and a board made of the same wood used in the film. The board tipped immediately and started to sink. Point for Cameron. Next, “Jack Savage” and “Rose Hyneman” did a full-scale test in the water, scaling up the board’s buoyancy to adjust for their increased mass as stand-ins for the actors — and outfitting “Rose” with a period-accurate life jacket made with the same materials and buoyancy as the one Winslet wears in the movie. It took “Jack” multiple attempts to be able to climb aboard and stabilize the board. But it sunk low enough in the water that drowning after loss of motor control would have been a danger. That’s when they tied Rose’s life jacket underneath the board, which raised it enough that they could position 80 percent of their bodies out of the water while resting on the board without needing to hold on. They made it 63 minutes. “With all we’ve learned, I think Jack’s death was needless,” Hyneman concluded. So yes, it’s plausible that both Jack and Rose could have survived on the board if they’d MacGyvered her life jacket.

Cameron’s good-humored response: “I think you guys are missing the point here. The script says Jack died. He has to die. So maybe we screwed up and the board should have been a little tiny bit smaller, but the dude’s goin’ down.”